In Legacy, you dont have time for you´re Burn deck to get high X Cost. So I would remove
Banefire and Bonfire.
Also I would suggest to run
Overmaster in Sideboard if you like that Card.
Basicly try to Play some 1 and 2 mana spells so, that the extra carddraw can be played faster
(Although 5 dmg for 3 mana is a bit weak. but i gues it gets around of Leyline of Sanctury
)
If you Need sugestions on what to Play in Burn:
http://deckstats.net/decks/42930/292315-burn-legacy/de